When used on wrought iron the top face may, with advantage, be given top rake as in [Fig. 962], which on account of causing the tool to cut easier, will reduce the spring of the work w in the direction of arrow a. For brass work, however, the top should be ground in an opposite direction, as in [Figs. 963] and [964], which will enable it to cut smoother and with less liability to rip into the metal, especially if the tool requires to be held far out from the tool post. To capacitate the tool to cut a groove close up to a shoulder, it should be forged to the shape shown in [Fig. 965]. As it is very subject to spring, it should not, unless the conditions are such as to give rigidity to both the work and the tool, be set above the work centres.
Fig. 966.
When a grooving or parting tool is to be used close up to the lathe dog, its cutting end may be bent at an angle, as in [Fig. 966], so that it may be adjusted on the lathe rest, so that the work driver will not strike against the slide rest.
Fig. 967.
